java.lang.ClassCastException: org.apache.poi.hssf.usermodel.HSSFRichTextString cannot be cast to java.lang.String at java.lang.String.compareTo(Unknown Source) at java.util.TreeMap.getEntry(Unknown Source) at java.util.TreeMap.containsKey(Unknown Source) at java.util.TreeSet.contains(Unknown Source) at com.test.ReadExcelFile.showExelData(ReadExcelFile.java:154) at com.test.ReadExcelFile.main(ReadExcelFile.java:121)